Abstract

Two coherent beams, A₁ and A₂ were horizontally polarized, crossed in the center of an electrically poled BaTiO₃ crystal at an angle of 46°, with angles of incidence 20.5° and 25.5° respectively. The powers were varied from 2 mW to 10 mW for A₁, and 5 mW to 13 mW for A₂. A₁ was found to self pump individually, but not A₂. They both self pumped under simultaneous pumping. With A₁ = 5 mW and A₂ = 9 mW, A₁, under individual pumping, showed minor pulsations in its self pump A₁. A₂ does not self pump. However, under simultaneous pumping, strong coherent oscillations were observed in both. When A₁ = 0.16 mW and A₂ = 13 mW, A₂ barely showed self pumped oscillations at the rate of 3 per 15 min while A₁ did not individually self pump. Under simultaneous pumping, A₁ and A₂ both showed self pumped oscillations at the rate of 5 per 15 min. As 2 mW and 13 mW represent approximately the threshold values of the laser power required for A₁ and A₂ in their respective quadrants to cross the threshold of γL = 2.34 to self pump, the coupling parameter γ per unit length can be estimated to be 6.5 times larger than that for A₂ in their respective quadrants.

© 1992 Optical Society of America